Hi, I recently swapped graphics cards on my HP Pavilion 500-199 and it will not boot. While I swapped the graphics card with an XFX Radeon HD 6870, I also changed the PSU for a EVGA 500W PSU. When i press the power button, the fans would spin, but there would be no display on the monitor. I tried swapping back to the old graphics card and PSU, but nothing would appear on the screen. I reconnected all cables, tried clearing the cmos, and switched the display cable, but nothing would work. Can anyone help me please? Thanks.